Add interceptor to resourceHandlerMapping

The resourceHandlerMapping in the MVC Java config is not configured
with any interceptors, and in particular those added through the
InterceptorRegistry, which are otherwise added to all other handler
mapping beans created by the config. This means that the
ResourceUrlProviderExposingInterceptor (added in 4.0) is also not
used for resource requests.

This change ensures the ResourceUrlProviderExposingInterceptor is
configured on the resourceHandlerMapping.

Issue: SPR-12279

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -68,6 +68,7 @@
 import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.HandlerExceptionResolver;
+import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.handler.AbstractHandlerMapping;
@@ -379,9 +380,15 @@ public HandlerMapping resourceHandlerMapping() {
 		addResourceHandlers(registry);
 
 		AbstractHandlerMapping handlerMapping = registry.getHandlerMapping();
-		handlerMapping = (handlerMapping != null ? handlerMapping : new EmptyHandlerMapping());
-		handlerMapping.setPathMatcher(mvcPathMatcher());
-		handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
+		if (handlerMapping != null) {
+			handlerMapping.setPathMatcher(mvcPathMatcher());
+			handlerMapping.setUrlPathHelper(mvcUrlPathHelper());
+			handlerMapping.setInterceptors(new HandlerInterceptor[] {
+					new ResourceUrlProviderExposingInterceptor(mvcResourceUrlProvider())});
+		}
+		else {
+			handlerMapping = new EmptyHandlerMapping();
+		}
 		return handlerMapping;
 	}
 

spring-webmvc/src/test/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupportExtensionTests.java

@@ -140,6 +140,9 @@ public void handlerMappings() throws Exception {
 		assertEquals(TestPathMatcher.class, handlerMapping.getPathMatcher().getClass());
 		chain = handlerMapping.getHandler(new MockHttpServletRequest("GET", "/resources/foo.gif"));
 		assertNotNull(chain.getHandler());
+		assertEquals(Arrays.toString(chain.getInterceptors()), 2, chain.getInterceptors().length);
+		// PathExposingHandlerInterceptor at chain.getInterceptors()[0]
+		assertEquals(ResourceUrlProviderExposingInterceptor.class, chain.getInterceptors()[1].getClass());
 
 		handlerMapping = (AbstractHandlerMapping) this.config.defaultServletHandlerMapping();
 		handlerMapping.setApplicationContext(this.context);